1. Field of the Invention
This invention relates to apparatus for manufacturing a structure composed of a central elongated member and a pair of end members extending in a common direction from the central elongated member, and, more particularly, to apparatus for manufacturing a valance combining mitered sections of extruded stock with a heat-formed decorative trim strip.
2. Background Information
Valances, or cornices, have been used for many years as interior decorations covering the mechanisms for attachment and movement of window coverings, such as curtains, drapes, shades, and blinds. Such mechanisms are typically adjacent the top of windows, with the window coverings hanging downward therefrom. For example, valances where used to cover the cord and pulley arrangements used to operate pull-up curtains developed in Europe in the latter part of the seventeenth century.
Due to the large number of widths and types of windows, and due to the variety of window coverings which must be accommodated, conventional methods for making valences have relied on materials cut to size and assembled for individual windows. For example, early valances were wooden box structures covered with fabric. More recently, buckram has been used, being fastened along the front face and ends of a board mounted to the wall above a window by means of brackets. The buckram covering, which is composed of a coarse linen or hemp cloth stiffened by sizing, is cut to shape, extending downward from the board to a decorative edge having, for example, a scalloped pattern, and folded at the corners to form return sections extending along the ends of the board to the wall.
Another trend in window coverings has been the replacement of soft draperies and curtains with relatively hard materials having straight edges, such as vertical blinds. These new materials are individualized by means of colors and textures. Valences composed of extruded plastic structures covered with decorative strips are used to match the visual effect of these window coverings. The decorative strip may be, for example, the same material and color as the vertical blind strips descending from a valance. A valance of this type conventionally consists of a front member extending above the window and of a end member extending toward the wall at each end of the front member.
A particular problem with this type of valance concerns the treatment of the decorative strip at the corners where the front member and the end members are joined. One conventional method of dealing with this problem has been to terminate the decorative strip at the corner, so that the portions of the decorative strip extending along the end members of the valance are separate from the portion extending along the front member thereof. A problem with this method arises from the fact that the decorative strips do not lie flat; they are bowed so that an aesthetically undesirable large gap is seen between the strip members extending in mutually perpendicular directions away from the corner.
Another conventional method for dealing with the decorative strip at the valance corners is to provide an underlying corner member providing a gentle curve between the flat surfaces on which the strip is held in the strip is held in the end and front members. When the valance is assembled, the strip is curved around each corner member at a generous radius established by the corner member. This generous radius is needed to allow the curvature of the strip. One disadvantage of this method is overall appearance of the finished valance is established and therefore limited by the method chosen for handling the corners. The overall appearance is one of straight lines and flat surfaces being joined by curved surfaces having generous radii. This type of appearance was popularized in the mid- to late-1930""s, being incorporated into the cover designs of clocks, radios, thermostats, etc.
Thus, what is needed is a method for manufacturing a valance having an accurately formed corner with a more modern squared appearance, around which a continuous decorative strip is formed.
Furthermore, valances made with joined extrusions tend to have central members extending rearward toward the wall for attachment to the end members, which are made from stock of differing cross members. What is needed is a method allowing relatively thin extrusions, common with one another, to be joined at mitered edges.
Thus, a first objective of the present invention is to provide apparatus for manufacturing a valance having a central member, two end members, and a decorative strip formed at square corners to extend along the central member and end members.
Another objective of the present invention is to provide apparatus for manufacturing a valance having minimum complexity where the central and end members are joined at corners.
Another objective of the present invention is to provide apparatus for manufacturing a valance having a central member and end members formed from common extruded stock.
In accordance with one aspect of the invention, there is provided apparatus for cutting mitered surfaces in an elongated member to form a structure including a central member and a pair of end members extending in a common direction from ends of the central member, with a first side of the elongated member forming intersecting surfaces of the structure, and with the first side of the elongated member including longitudinally-extending fixture engaging features. The apparatus includes a power saw, saw mounting means, and a fixture including first and second workpiece locating features. The power saw moves a saw blade within a sawing plane. The saw mounting means mounts the power saw to be slidable in a first direction parallel to the sawing plane. The fixture holds the elongated member to extend in a second direction within a fixture plane, wherein the fixture plane and the sawing plane intersect at a 45-degree angle, wherein the sawing plane is inclined to extend in the second direction away from an intersection of the sawing plane and the fixture plane, and wherein the fixture includes longitudinally-extending guiding features engaging the fixture engaging features of the elongated member. The first workpiece locating feature in the fixture is offset through a first distance from the intersection of the sawing plane and fixture plane opposite the second direction. The second workpiece locating feature in the fixture is offset through a second distance from the intersection of the sawing plane and the fixture plane in the second direction.